An Arctic methane 'time bomb' brought about by rapidly thinning permafrost could cost the world up to $60 Trillion, the size of the entire global economy, a group of economists and polar scientists warned on Tuesday.

A new University of Georgia study that is the first to examine comprehensively the magnitude of hydrocarbon gases released during the Deepwater Horizon Gulf of Mexico oil discharge has found that up to 500,000 tons of gaseous hydrocarbons were emitted into the deep ocean.